Fuse cartridge



INVENTOR Aug. 14, 1923.

F. A. FELDKAMP FUSE CARTRIDGE Filed July 22, 1920 Patented Aug. 14, 19423.

UNITED STATES FREDERICK A. FELDKAMP,

OF NEWARK, NEW JERSEY.

FUSE CARTRIDGE.

Application led July 22, 1920. Serial No. 398,203.

To all whom it may concern Be it known that I, FREDERICK A. FELD- KAMP, a citizen of the United States, residing at Newark, in the .county of Essex and State of New Jerse have invented certain new and useful mprovements in Fuse Cartridges; and I do' hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanyingdrawings, and to characters of reference marked thereon, which form a part of this specification.

The present invention has reference, generally, to electrical fuse devices; and the invention relates, more particularly, to a novel construction of electrical fuse cartridge which can be operated repeatedly without necessity for refilling or replacingr new fuse elements therein after the same blows The invention has for its principal object to provide a novel construction of electrical fuse cartridge of standard exterior shape and arrangement adapted for insertion in the well known holding clips when;

placed in use, but which possesses a novel arrangement and character of fuse element which, while initially solid or rigid, will melt and liquefy when subjected to heat induced by overloads or short circuiting of the electrical current passed therethrough, so that a shift of said fuse element from an initial operative osition and relation to the cartridge terminals occurs, whereby the electric circuit served is interrupted. Saidnovel character and arrangement of fuse element is such, that after the same `operates to interrupt the electric circuit it serves, the same will again solidify so as to be rendered ready for renewed operation,'and the same can thereupon be repeatedly placed in service again by merely reversin `the end to end engagement of the cartri ge with its holding clips.

Other objects of the 'present invention, not at this time more particularly enumerated, Will be clearly understood from the following detailed description of the same.

Withv the various objects of th invention in view, the same consists, primarily, in the novel construction of electrical fuse cartridge hereinafter set forth; and, the invention consists, furthermore, in the novel arrangements and Y combinations of the y various devices and parts, as well as in the details of the construction of the same, all of which will be hereinafter more fully described, and then finally embodied in the claims appended hereto.

The invention is clearly illustrated in the accompanying drawings, 1n which Figure l is a vertical longitudinal section of oneI form of the novel construction of electrical fuse cartridge made according to and embodying the principles of my pres'- ent invention.

Figure 2 is an end view of the same, and Figure 3 is a transverse section through the same, taken on linel 3- 3 in said Fi ure 1.

igure 1 is a vertical longitudinal section of asom'ewhat modified form and arrangement of the novell electrical fuse cartridge; Figure 5 is an end view of the same; Figure 6 is a transverse section through the same, taken on line 6-6 in said Figure 4; andl Figure 7 isv another transverse section through the same, taken on line 7-7 in said Figure 4.

Figure 8 is a vertical longitudinal section of another modified form and arrangement of my novel electrical fuse cartridge.

Similar characters' of yreference are employed in all of the hereinabove described views, to indicate corresponding parts.

Referring now to said drawings, the reference-character 1 indicates a cartridge body made of some suitable insulating material capableof resisting the effects of heat generated by the electric current passed through the fuse cartridge, and also capable of resisting both the action of any arc produced or pressure created within the interior thereof. Materials which, for example, may .be successfully utilized for said cartridge body l may be a molded material such as bakelite, or Silica, or porcelain.

Threaded or otherv switch-element chamber 2 is an internally threaded bushin 5. Said lcartridge body 1 is preferably o cylindrical shape, and is provided at its ends with the respective external contact caps 6 and 7, which may be retained in place by the metallic screws 8, which not only serve to so retain said caps in place by screwing into said bushings 5, but also serve as contact points for engaging the switch element in electrical connection with either one cap or the other. The switch ele` ment comprises a body of mercury 9 which will lill or occupy a little more than onehalf of said switch-element chamber 2. Arranged to pass through or connect with each cap 6 and and into the respective ends of said fuse-element chamber 4, are contact points 10, preferably in the form of nickel steel screws, the ends of which are respectively exposed at the ends of said fuse-element chamber 4. The novel fuse element comprises a body of metallic allo 11 possessing a low melting point (meltlng, e. g., at temperatures ranging from 200 to 400 degrees F.), said fuse element providing a mass filling or occupying substantially onehalf of said fuse-element chamber 4. An alloy which answers very satisfactorily the purposes and desiredfunctioning demanded of the novel fuse element may, e. g., consist of bismuth, tin and lead, in proportions approximating 2 parts bismuth, 1 part tin, and 1 part lead; an alloy of lead and antimony may also be used. Fixed in'said intermediate wall 3 dividing said switch element chamber 2 from said fuse element chamber 4 is a transverse interconnecting contact element or plug 12, one end of which is exposed at the side' of said fuse element chamer 4 and the other end of which is exposed within or at the side of said switch element chamber 2.. `Said contact element or plug 12 is located centrally, so as to be positioned relative to said respective chambers 2 and 4 at points midway between their ends.

When in use the novel fuse cartridge is disposed in such a position thatits longitudinal axis is referably vertical, the holding clips, by w ich the same is connected in the circuit to be served, being so arranged as to ermit such positioning of said fuse cartri ge. Normally'the fuse element 11 is in a solidified state, occupying the upper half of the fuse element chamber 4, with its one or upper end electrically engaged with the contact point 10 of one of the exterior cartridge terminal caps (the same being shown in the drawings so electrically engaged with the upper ATterminal cap 6), while its other or lower end is electrically engaged with the interconnecting contact element or plug 12. The switcli element, comprised of the mercury 9, being constantly in a fluid-state, and thus free tp respond to the pull of gravity, occupies the lower half of the switch-element chamber 2, with its one or lower end' electrically engaged with the contact point 8 of one of the exterior cartridge terminal caps `(the same being shown in the drawings so electrically engaged with the lower,ter minal cap 7), while its other or upper end is electrically engaged with the interconnecting contact element or plug 12. When the fuse cartridge is thus operatively connected in circuit, the current entering from one pole of the `cartridge holding clips through the terminal cap 6 passes downwardly through thefuse element 11, and thence across the interconnecting contact element or plug'12 into and through the mercury 9 to the terminal cap 7, and thence into the other pole of the cartridge holding clips. If an overload or short circuit of the electric current occurs, the resistance offered by the fuse' element 11 to its passage will so increase the temperature of said fuse element, that the same will m'elt or liquefy. The melting of the fuse element will begin at its upper end at the place of contact thereof with said contact point 10, since the latter being preferably made of a high resistance metal such as nickel steel and since the heat generation increases proportionally to the resistance, it follows that such place of contact will first reach a melting temperature. By reason of this effect the fuse element 11 will first liquefy at its upper end thus assurin a complete separation or parting thereof rom said contact point 10, when the melting effect roduced as to the fuse element roceeds ownwardly to its lower end. on the complete melting or liqueiication of) the fuse element, the same immediately responds to the pull of gravity, whereby it 1s caused to drop or plunge downwardly to the lower end of said fuse element chamber 4, and consequently the ath of the current is broken or interrupted tween the terminal cap 6 and said interconnecting contact element or plug 12. As a further aid to and assurance of the'melting or liquefying of the upper end of the fuse-element fuse-element chamber 4 may be tapered from its central portion toward its respective ends so 'that the cross sectional area of the fuse element 11 will diminish toward the place of engagement with said contact point 10, at which place the bulk of the fuse element will be .considerably reduced as compared to the bulk of the opposite or lower end thereof. This latter arrangement and shaping of the fuse-element chamber 4, while referable rhaps, is not absolutely .essentia hence I di not limit myself to such construction. In all cases, however, the desideratum is to provide a condition which will assure a slightly prior liquefying of the fuse element at its point of engagement with the terminal cap contact means.

'slightly prior to the lower end thereof, the '4 .45 fied form of my novel fuse cartridge, which comprises two internal tubular sections 13 After the fuse element 11 liqueies, under the conditions and in .the manner vabove stated, and drops to the opposite end of the fuse element chamber 4, it will be apparent -that not only is the electric circuit intertion to the electrical circuit served, will be to remove the fuse cartridge from the holding clips and reverse or invert the same in the latter, .whereupon the terminal cap 7 will be uppermost, with the fuse elementy electrically engaged therewith and-occupying an upwardly raised position relative to the fuse element chamber 4, and the terminal cap 6 will be thereupon electrically engaged with said fuseelement 11 by reason of the fact that the mercury 9 will, under gravity, when the fuse cartridge is reversed or inverted, drop to the opposite end of said switch element chamber 2, to afford a bridging connection between said terminal cap 6 and said interconnecting contact point or plug 12. From the above it will bevclearly understood, that my novel fuse cartridge is provided with self-contained fuse elements adapted for repeated service, that is, the same may be used over and over again without necessity of refilling or replacing any parts thereof, and merel by inverting or reversing the position o the same. in the holding clips after the occurrence vof each blowing of the fuse. p

Referring now to Figures 4 to 7 inclusive of the drawings, I `have illustrated a modiand 14, made of a suitable insulatingmaterial, and arranged end to end by being threaded into a metallic lcoupling member 15, which also serves as a centrally disposed interconnecting contact point functioning electrically in the same manner as does the point or plug 12 of the previously described construction. Said sections 13 and 14 as coupled by the member 15 provide a longitudlnal fuse-element chamber4, in which is disposed the novel fuse element 11. Arranged to extend around said coupled internalsections 13 and 14 is an outer cartridge casing or body 16, also m-ade of insulatingmaterial, but spaced concentrically from said coupled internal sections 13 and 14 to provide an intermediate concentric longitudinal switch-element chamber 2 in which is disposed the mercury 9 providing the fluid switch member. External caps 6 and 7 may be screwed or otherwise secured upon the respective ends of said outer casing 16 to close the ends of Said switch-element chamber 2, said caps being respectively provided with contact points 10 which enter the ends of said fuse element chamber 4. If desiredthe inner sides of the wall of said outer casing may be longitudinally corrugated, as

. shown more particularly in Figures 6 and 7 of the drawings, lthereby serving Atoy additionally re-enforce the cartrid e structure. From an inspection of the said igures 4 to 7 of the drawings, having` in mind the description of the roperation of my fuse above given, it will be apparent that the structure while somewhat modified in detail, is in principle the same, and will operate in the same manner.

` Referring now to Figure 8 of the drawing I have shown my novel fuse modified to an extent wherein the mercury switch element is omitted, and there is substituted therefor a hand manipulatable metallic switch element 17, which is pivoted at one end in electrical and mechanical connection with the coupling member 15', or equivalent means, so that its free end 18 is reversibly engageable either with the terminal cap 7 or the cap 6 as the case may. require. In using this form of my novel fuse cartridge care must be taken, that the fuse element 11 is always at the upper end of the cartridge, when the latter is placed in the holding clips, and that the switch member is then engaged with the lower cap. Of course, the

mercuryswitch element 9, being automatic in action, is preferable to the hand manipulatable switch above described.'

It'will be apparent that there are many ways of modifying the arrangements and details of construction of the devices and parts making up my novel fuse without departin from the principles of my invention, hence do not limit my invention to the exact arrangements and combinationsvof the various devices and parts, nor to the specific materials of which the same are made, as set forth in the above specification, nor do I confine myself to the exact details of the construction of said devices and parts as illustrated in the accompanying drawings.

' 1. A fuse device,'comprising a container havingv external terminal 'caps,"a. switching device, and a fuse normally in fseries with said switching device to 'connect said caps but which moves into parallel connection with said switching device whenv blowing to disconnect said caps.

2. A fuse device, comprising a chambered container providing a switch element chaminto electrical engagement with a terminal cap, a fuse ele-ment, in the other chamber normally arranged in electrical engagement with the oppositeterminal cap, means normally connecting said switching element and said fuse element in series, said fuse element being adapted vwhen blowing to disconnect itself from the engagedterminal cap and drop into electrical engagement withthe opposite `terminal cap to electrically disconnect said caps', and said fuse device being made ready for renewed use by inverting the same to permit said switching element to move into series relation with said fuse elementf to again electrically connect said caps.

3. .A fuse device, comprising a container having internal longitudinally parallel chambers, external caps at the ends of said container, a contact plug with portions thereof exposed in said respective chambers intermediate the ends of the latter, a normall solid -fuse element possessing a low melting point whereby the same will liquefy when subjected to heat induced by abnormal current loads, said fuse element normally filling the upper portion of one chamber in bridging electrical connection between the upper terminal cap and said contact plug, and aiuid switching element normally filling the lower pfrtion of the other chamber in bridging electrical connection between said contact plug and said lower terminal An electric fuse device having an internally disposed fuse element in direct connection at one end with one pole of said device, reversible means establishing an indirect connection between the opposite end of said fuse element and the other p ole of said device, and said fuse element being adapted under current overloads to move axlally away from the first pole to break the circuit and thereupon directly connect itself with said second pole.

5. An electric fuse device having longitudinall parallel internal chambers between its po es, a bridging contact means between said chambers intermediate their ends, a

-fuse element in one chamber normally extending between one pole and said Contact means, a fluid conductor in the other chamber normally extending between said contact means and the opposite pole, said fuse element being adapted under current overlcads to move axially away from said first pole t0 break the circuit and thereupon connect itself between said second pole and said contact means, and inversion of said fuse device being adapted to cause said Huid conductor to move axially into operative position between said contact means and said first ole.

6. n an electric fuse device, a normally rigid fuse element directly connected with one pole', reversible means for indirectly connecting said fuse element with the opposite pole, and said fuse being adapted under predetermined current overloads to melt and flow away from contact with saidirst pole into engagement with said second pole to thereupon again solidify in such connection whereupon reversal of said indirect connecting means again connects said fuse clement between the poles for renewed use.

In testimony, that I claim the invention set forth above I have hereunto set my hand this 16th day of July, 1920.

FREDERICK A. FELDKAMP.

Witnesses:

Gronon D. RICHARDS, WM. S." LEONARD. 

